The present invention relates to a door lock unlockable from the indoor side and, more particularly, a door lock for use in walk-in type large-size refrigeration chambers or compartments for electric power boards or feeder panels, improved to eliminate any accidental confinement of workers in the refrigeration chamber or compartment due to a careless locking operation at the outdoor side.
Door locks unlockable from the indoor side have been known. In the conventional door locks of the kind described, however, the major part of the indoor unlocking mechanism is concealed in the casing and only the manipulation end of the mechanism appears on the inner surface of the door panel. Therefore, it is quite difficult, particularly for those who are not familiar with the internal structure of the lock to immediately understand how to manipulate the manipulation end of the unlocking mechanism. The worker who has been accidentally confined in a chamber or compartment is unable to easily and immediately understand how to unlock, he will gradually have the jitters which in turn makes it difficult to take a calm attitude toward the relief and, in the worst case, will be upset or beside himself and lose the chance of escape by himself.